Multi-mode charging system for an electric vehicle

ABSTRACT

A method and apparatus that allows the end user to optimize the performance of an all-electric or hybrid vehicle and its charging system for a desired mode of operation is provided. The system of the invention includes multiple charging/operational modes from which the user may select. Each charging/operational mode controls the cut-off voltage used during charging and the maintenance temperature of the battery pack.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/321,279, filed Jan. 16, 2009, which is a continuation-in-part of U.S.patent application Ser. Nos. 11/818,838, filed Jun. 15, 2007;11/779,678, filed Jul. 18, 2007; and 12/058,047, filed Mar. 28, 2008;the disclosures of which are incorporated herein by reference for anyand all purposes.

FIELD OF THE INVENTION

The present invention relates generally to batteries and, moreparticularly, to a method and apparatus for providing different chargingand cooling modes for the battery pack of an electric vehicle.

BACKGROUND OF THE INVENTION

Batteries have been used for decades to supply power to a variety ofdifferent electrical and electromechanical devices. Early batteries,referred to as disposable batteries, were simply used until depleted andthen discarded and replaced with one or more new batteries. A newer typeof battery, referred to as a rechargeable battery, is capable of beingrecharged and then reused, therefore offering economic, environmentaland ease-of-use benefits compared to a disposable battery.

Although rechargeable batteries provide a much longer service life thandisposable batteries, their service life is not unlimited. Dependingupon the type of battery, a rechargeable battery can typically berecharged anywhere from 100 times (e.g., alkaline) to 1000 times (e.g.,lithium-ion, lithium-polymer) to 20,000 times or more (e.g., thin filmlithium). In addition to depending upon the type of battery chemistryinvolved, the number of cycles that a rechargeable battery can berecharged depends on a variety of other factors that include; (i) therate of charging (i.e., slow trickle charge versus fast charge), (ii)the level of charging (i.e., 75% of full charge, full charge,over-charged, etc.), (iii) the level of discharge prior to charging(i.e., completely depleted, still charged to a low level, etc.), (iv)the storage temperature of the battery during non-use, and (v) thetemperature of the battery during use.

Due to the high initial cost of rechargeable batteries, expensiveproducts such as laptop computers often incorporate relativelysophisticated power management systems, thereby extending battery lifeand allowing the use of smaller, lower capacity batteries and/orbatteries that utilize less expensive cell chemistries. One of the mostcommon power management techniques is to place certain laptop componentsand peripherals, especially those that require relatively high levels ofpower to function, into either a standby mode or a low power usage modewhenever possible. Thus, for example, a laptop may provide two differentvideo screen brightness levels; high brightness when the computer isplugged in, and low brightness when the computer is operating on batterypower. This is also the primary purpose behind powering down the videoscreen when the computer is inactive for more than a short period oftime or placing wireless connectivity capabilities (e.g., Bluetooth,WiFi, WAN, etc.) or other non-essential peripherals in standby mode whenthey are not required.

A growing application for rechargeable batteries is that of electricvehicles. All-electric and hybrid vehicles, however, present a number ofengineering challenges, primarily due to the need for the rechargeablebattery pack of such a vehicle to meet the consumers' expectationsrelative to performance, range, reliability, lifetime and cost. Thepresent invention provides a battery pack recharging system and userinterface that helps achieve these goals.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus that allows theend user to optimize the performance of an all-electric or hybridvehicle and its charging system for a desired mode of operation.

In at least one embodiment of the invention, the electric vehicleincludes a multi-mode charging and operating system comprised of abattery charging system that utilizes a cut-off voltage selected from atleast three cut-off voltages, a battery cooling system for cooling theelectric vehicle's battery pack to a temperature within a temperaturerange selected from at least three temperature ranges, and useraccessible means for selecting a preferred mode from a plurality ofcharging/operational modes, wherein a first mode utilizes a firstcut-off voltage and a first temperature range, a second mode utilizes asecond cut-off voltage and the first temperature range, a third modeutilizes a third cut-off voltage and a second temperature range, and afourth mode utilizes a third cut-off voltage and a third temperaturerange. The system can further include a battery heating system forpreventing the battery pack temperature from falling below a presettemperature threshold when the battery system is coupled to the chargingpower source and the fourth mode is selected by the selecting means. Theuser accessible selecting means can utilize a touch-sensitive screen, adisplay system and a plurality of associated switching means, aplurality of switching means, a rotating switch, a voice recognitionsystem, or a remote mode selector such as an RF remote or a remoteutilizing any of a variety of network communication systems. The systemcan further include at least one mode indicator. The system can furtherinclude means for switching between the preferred mode and a defaultmode after a preset period of time or upon the occurrence of a presetcondition. The system can further include user accessible means forselecting the default mode from the plurality of charging/operationalmodes. The system can further include means for prompting the user toselect the preferred mode from the plurality of charging/operationalmodes.

In at least one embodiment of the invention, the electric vehicleincludes a multi-mode charging and operating system comprised of abattery charging system that utilizes a cut-off voltage selected from atleast three cut-off voltages, wherein the second cut-off voltage ishigher than the first cut-off voltage and wherein the third cut-offvoltage is higher than the second cut-off voltage; a battery coolingsystem for cooling the electric vehicle's battery pack when the batterycharging system is coupled to an external charging power source, thebattery cooling system maintaining the battery pack temperature withinat least a first temperature range, a second temperature range of athird temperature range; a charging/operational mode selector with atleast four available charging/operational modes, wherein the firstcharging/operational mode defines a standard mode and utilizes thesecond cut-off voltage and the second temperature range, wherein thesecond charging/operational mode defines a storage mode and utilizes thefirst cut-off voltage and the second temperature range, wherein thethird charging/operational mode defines an extended driving range modeand utilizes the third cut-off voltage and the third temperature range,and wherein the fourth charging/operational mode defines a performancemode and utilizes the third cut-off voltage and the first temperaturerange; and a mode display that indicates which charging/operational modehas been selected.

In at least one embodiment of the invention, a method of setting acharging/operational mode of an electric vehicle is provided, the methodcomprising the steps of displaying a plurality of user accessiblecharging/operational modes, selecting a preferred mode from theplurality of user accessible charging/operational modes, displaying anindicator of the selected mode, adjusting a cut-off voltage andmaintaining the temperature of the battery pack within a range oftemperatures when the electric vehicle is plugged into an externalcharging power source, wherein the cut-off voltage and the temperaturerange are based on the selected mode. The method can further comprisethe step of reverting to a default charging/operational mode from thepreferred charging/operational mode after a preset period of time, orafter the electric vehicle has cycled from an operational mode to astandby mode a preset number of times.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 graphically illustrates the effects of charging cut-off voltageon battery life;

FIG. 2 graphically illustrates the effects of temperature on cellvoltage and discharge capacity;

FIG. 3 graphically illustrates the effects of storage temperature onbattery capacity;

FIG. 4 is a high-level view of the primary vehicle subsystems impactedby a battery charging system designed in accordance with a preferredembodiment of the invention;

FIG. 5 illustrates a touch-sensitive display screen associated with oneembodiment of a charging/operational mode selector;

FIG. 6 illustrates a non-touch-sensitive display used in conjunctionwith other switching means in an alternate embodiment of acharging/operational mode selector;

FIG. 7 illustrates a simple charging/operational mode selector that doesnot require a display interface;

FIG. 8 illustrates a simple means of indicating the selectedcharging/operational mode; and

FIG. 9 illustrates a system for remote charging/operational modeselection.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

In the following text, the terms “battery”, “cell”, and “battery cell”may be used interchangeably and may refer to any of a variety ofdifferent rechargeable cell chemistries and configurations including,but not limited to, lithium ion (e.g., lithium iron phosphate, lithiumcobalt oxide, other lithium metal oxides, etc.), lithium ion polymer,nickel metal hydride, nickel cadmium, nickel hydrogen, nickel zinc,silver zinc, or other battery type/configuration. The term “batterypack” as used herein refers to multiple individual batteries containedwithin a single piece or multi-piece housing, the individual batterieselectrically interconnected to achieve the desired voltage and capacityfor a particular application. The term “electric vehicle” as used hereinrefers to either an all electric vehicle, also referred to as an EV,plug-in hybrid vehicles, also referred to as a PHEV, or a hybrid vehicle(HEV), a hybrid vehicle utilizing multiple propulsion sources one ofwhich is an electric drive system.

FIGS. 1-3 illustrate several battery characteristics for an exemplarybattery pack. It should be understood that different battery packs, forexample those using a different cell chemistry, will exhibit differentprofiles than those shown in FIGS. 1-3, and that these figures are onlymeant to be illustrative, not limiting.

FIG. 1 is a graph that illustrates the effects of charging cut-offvoltage on battery life, the cut-off voltage being the voltage at whichcharging is terminated. Utilizing a cut-off voltage of 4.15 volts (curve101), initially the battery pack achieves a higher capacity than thatobtained using a cut-off voltage of 4.10 volts (curve 103). However,after approximately 200 charging cycles, the capacity of the batteryusing the lower cut-off voltage is greater than that of the batteryusing the higher cut-off voltage, illustrating that the useful lifetimeof a battery pack can be dramatically extended by simply loweringcut-off voltage. Unfortunately lowering the cut-off voltage hasconsequences to other aspects of the battery pack's performance, inparticular capacity, since a battery charged to a higher voltageexhibits a greater capacity than the same battery charged to a lowervoltage.

FIG. 2 is a graph illustrating the effects of temperature on the cellvoltage and discharge capacity of an exemplary battery. In the figure,curve 201 corresponds to a temperature of 40° C., curve 202 correspondsto a temperature of 30° C., and curve 203 corresponds to a temperatureof 20° C. As illustrated, an increase in operating temperature from 20°C. to 40° C. dramatically improves discharge capacity which, in turn,can lead to both improved vehicle performance (e.g., fasteracceleration) and improved driving range for an electric vehicle usingsuch a battery pack. A drawback, however, of operating at a highertemperature is the effect such a temperature has on battery life,specifically shortening the battery's life. Another adverse effect ofhigher temperatures is that a battery will typically exhibit highernon-recoverable capacity loss as the temperature is increased. Thisbattery characteristic is illustrated in FIG. 3 in which curve 301 isfor a battery pack cycled at 35° C. and curve 303 is for a battery packcycled at 55° C. As shown, by decreasing the storage temperature of abattery, it is able to retain a much higher capacity over a longer cyclelife.

There are many other battery characteristics that must be taken intoaccount during the design of the drive system, battery pack andattendant charging system of an all-electric or hybrid vehicle. Forexample, the depth of discharge which the system allows, or that thesystem is designed to accommodate, will affect a battery's life. Formost battery chemistries, frequently discharging the battery more than70 to 80 percent of rated capacity will lead to decreases in batterylife.

FIG. 4 is a high-level view of the primary vehicle subsystems impactedby a battery charging system designed in accordance with a preferredembodiment of the invention. It will be appreciated that a vehicle canutilize other subsystem configurations while still retaining themulti-charging mode capabilities of the present invention. As shown,system 400 includes a power control subsystem 401, a battery pack 403, abattery cooling subsystem 405, a battery heating subsystem 407, and auser interface 409. In a preferred embodiment, battery cooling system405 and battery heating system 407 are combined into a temperaturemanagement system 408.

Power control subsystem 401 is comprised of a charging module 411 thatcontrols and monitors cut-off voltage during charging. Charging module411 may also control and monitor the charging rate. Preferably, and asdescribed in further detail below, power control subsystem 401 alsomonitors the temperature of battery pack 403 and controls thattemperature using battery cooling subsystem 405. In at least oneembodiment, a battery heating subsystem 407 is also used by powercontrol subsystem 401 to achieve the desired battery pack operatingand/or storage temperature. An exemplary battery temperature controlsystem is described in detail in co-pending U.S. patent application Ser.No. 11/786,108, filed Apr. 11, 2007, the disclosure of which isincorporated herein for any and all purposes.

Power control subsystem 401 also monitors the state of charge forbattery pack 403, for example via charging module 411. Preferablysubsystem 401 is also capable of monitoring the rate of discharge ofbattery pack 403, both during vehicle operation and vehicle storage. Inaddition, in at least one embodiment subsystem 401 monitors and storesin on-board memory the number of charging cycles to which the batteryhas been subjected. Preferably for each charging cycle the cut-offvoltage and other charging parameters are monitored and stored inmemory, thereby providing information that can be used to gauge therelative health of battery pack 403 and its expected lifetime.

Although charging module 411 is preferably integrated within powercontrol subsystem 401 as shown, in at least one alternate embodimentcharging module 411 is external to both the power control subsystem 401and the vehicle. In such an embodiment, preferably the portion of thecharging module that converts external power to a power level (e.g.,voltage) that is compatible with battery pack 403 is external to thevehicle while a second portion of the charging module that controlscharging characteristics such as cut-off voltage, charging rate, etc. isinternal to the vehicle. Alternately, the entire charging module can beexternal to the power control subsystem 401 and the vehicle.

In at least one preferred embodiment, battery pack 403 is configured tobe plugged into, or otherwise connected to, an external power source 413via charging module 411. A municipal power grid is one example of anexternal power source 413. Charging module 411 insures that the powerfrom source 413 is converted to a form of power storable by battery pack403. For example, charging module 411 typically includes an AC to DCrectifier in order to convert power from the power source to thatrequired by battery pack 403. In at least one embodiment, battery pack403 is charged in whole or in part by a power generator 415 that iscontained within the vehicle, i.e., an on-board power generator, whichis coupled to the battery pack via charging module 411. As on-boardpower generator 415 is not necessary to the implementation of theinvention, it is shown in phantom. It will be appreciated that in someembodiments, while external power source 413 is preferred for providinga full charge to battery pack 403, internal power source 415 can be usedto augment the charge within the battery pack, for example by chargingbattery pack 403 during vehicle use, thereby extending driving range. Inat least one embodiment, internal power source 415 is a regenerativebraking system.

Power control subsystem 401 also controls the power coupled from batterypack 403 to vehicle propulsion motor 417, for example using a powerelectronics module (PEM) 419. Power electronics module 419 is used toinsure that the power delivered to motor 417 has the desired voltage,current, waveform, etc. Thus, for example, power electronics module 419preferably includes a DC to AC inverter, as well as the necessarycontrol circuitry/processor to implement the various selectable chargemodes as described in detail below. It will be appreciated that vehiclepropulsion motor 417 can be comprised of a single electric motor, ormultiple electric motors.

User interface 409 is preferably integrated into the vehicle's userinterface, although interface 409 can be implemented in other ways asdescribed in detail below. Interface 409 provides a means for the userto control the selection of the charging mode as well as associatedparameters. Preferably interface 409 also provides means for identifyingwhich mode the vehicle is in at any given time, as described furtherbelow.

Charging/Operational Modes

The system of the present invention allows the user to select theoperational mode of a vehicle, more specifically aspects of thecharging, battery and power control systems that affect the performanceof an electric vehicle (i.e., all electric or hybrid) and the batterypack, as well as the life expectancy of the battery pack. Preferredmodes of operation will now be described in detail.

Standard Mode—In the Standard Mode, the system is configured to providethe optimal compromise between performance, driving range and batterylife. In general, the Standard Mode will limit the cut-off voltageduring charging to approximately 70%-95% of the rated capacity. In apreferred embodiment, the cut-off voltage in the Standard Mode is set toapproximately 4.10 volts. The Standard Mode is intended to maintain thebattery pack at a relatively cool temperature during both vehicleoperation (i.e., driving) and when plugged in, preferably cooling thebattery pack to a temperature within the range of approximately 30° C.to 35° C. during vehicle operation, and within the range ofapproximately 20° C. to 25° C. when the vehicle is plugged in to theexternal power source.

Storage Mode—The Storage Mode is configured to optimize battery lifewhen the vehicle is stored for an extended period of time, for example,for a period of time greater than 2 or 3 weeks. In this mode, thecut-off voltage during charging is limited to approximately 30%-70%, andmore preferably to approximately 30%-50%. In a preferred embodiment, thecut-off voltage in the Storage Mode is set to approximately 3.80 volts.As in the Standard Mode, the battery pack temperature is maintained at arelatively cool temperature, preferably in the range of approximately20° C. to 25° C., when the charging system is coupled to an externalpower source. In at least one embodiment, once Storage Mode is selected,and assuming that the vehicle is plugged in rather than operating andthat the battery pack's state of charge is greater than a preset value(e.g., 50%), the system actively lowers the charge state to the presetvalue, thereby helping to prolong battery life. Preferably the systemactively lowers the charge state by subjecting the battery pack to aload (e.g., turning on a light(s), fan, dummy load, etc.).

Extended Driving Range Mode—This mode, also referred to as the Max RangeMode, optimizes the system for maximum driving range, i.e., distance.During vehicle operation, the battery is kept relatively warm, therebydecreasing battery impedance and achieving greater discharge capacity.In a preferred embodiment, during vehicle operation in this mode, thetemperature is not cooled until the temperature rises to about 40° C.The cooling system then operates to keep it within the range ofapproximately 37° C. to 40° C. If the Max Range Mode is selected and thevehicle is plugged into an external power source, the battery pack iscooled to a lower temperature than normal, preferably in the range ofapproximately 15° C. to 17° C. During charging the maximum cut-offvoltage is used, i.e., approximately 90%-100% of rated capacity. In thepreferred embodiment, the cut-off voltage is set to approximately4.15-4.18 volts.

Performance Mode—This mode is intended to achieve the best vehicleperformance available, at the cost of both battery life and range. Ingeneral, the Performance Mode uses the maximum cut-off voltage duringcharging, i.e., approximately 90%-100%. In one embodiment, the maximumcut-off voltage is set to approximately 4.15 to 4.18 volts. In apreferred embodiment, during vehicle operation the battery packtemperature is allowed to rise to a temperature within the range ofapproximately 37° C. to 40° C. and then cooled to maintain thetemperature within this range. In this mode when the vehicle is pluggedinto the external power source, preferably the battery temperature iscooled (if necessary) to a temperature within the range of approximately35° C. to 40° C.

In at least one alternate embodiment, in addition to the above-describedbattery pack cooling conditions, when the vehicle is plugged inpre-heating is used, as necessary, to insure that the battery packtemperature does not fall below a preset temperature, for example 33° C.In particular, in this alternate embodiment the battery pre-heater isenabled when the battery temperature falls below 33° C., and is thendisabled once a temperature of 35° C. is reached.

In addition to charging the battery pack to the maximum level andmaintaining the battery at a relatively high temperature, in at leastone embodiment when the user selects the Performance Mode, the powercontrol subsystem via the power electronics module provides anadditional performance boost. Specifically, in this embodiment when thePerformance Mode is selected, the system provides a temporary increasein the available current that can be supplied to motor 417. In anexemplary system, the available current is increased from 850 amps rmsto 900 amps rms. As the increase in current stresses many vehiclecomponents (e.g., PEM 419, motor shaft, transmission, etc.), preferablythe current boost is of very limited duration. For example in oneembodiment, the current boost is only allowed for a maximum duration of5 seconds. Preferably other limitations are placed on the current boost,for example limiting it to one use per Performance Mode selection. Inorder to limit system stress, the current boost can also be limited to apredetermined number of times per time period, the time period beingmeasured in days, weeks or months.

It will be appreciated that the cut-off voltages as well as the optimaltemperature ranges provided above relative to the describedcharging/operational modes of operation are based on a specific vehicleand battery pack. The inventors envision that other vehicles and/orbattery types may require different operational parameters (e.g.,cut-off voltages, battery temperatures, etc.) in order to achieve thedesired goals of optimizing the charging, battery and power controlsystems for such specific charging/operational modes as Standard Mode,Storage Mode, Extended Driving Range Mode and Performance Mode.

In a preferred embodiment of the invention, if the vehicle is pluggedinto external power source 413 during any of the above modes and batterypack charging has been completed, in addition to initiating battery packcooling in order to keep the battery within the preset temperaturerange, charging is re-initiated so that the battery is not used to powercooling subsystem 405. Charging re-initiation can start before, after,or at the same time as cooling subsystem initiation.

In at least one embodiment, the selection of a specificcharging/operational mode also impacts the charging profile employedwhile operating the vehicle. This embodiment requires some form of aninternal power generator 415. Preferably internal power generator 415utilizes a regenerative braking system, either alone or in combinationwith other power generation means (e.g., roof-mounted solar panels,etc.). In this embodiment, the state of charge of battery pack 403 ismonitored and maintained within a predefined range using the chargingcapabilities provided by the internal power generator. Preferably, inthe Standard Mode an average charge of approximately 50% is maintained;in the Storage Mode an average charge of 30-50% is maintained; and inthe Max Range and the Performance Modes an average charge ofapproximately 70% is maintained.

In at least one embodiment, when the vehicle is plugged into externalpower source 413, the power control subsystem 401 determines the voltageand current of the source. If the voltage is less than a preset value,e.g., 150 volts, or if the line current is less than or equal to apreset value, e.g., 12 amps, battery cooling is limited. This approachcan be used, for example, to shorten charge time. In a specificapplication, when subsystem 401 determines that the voltage/current ofthe external power source is less than the preset value, the batterytemperature is cooled to a temperature within the range of approximately37° C. to 40° C. regardless of the charging/operational mode selected,and once the battery pack temperature is less than 37° C., the coolingsubsystem is disabled.

Alternate Charging/Operational Modes

In an alternate embodiment of the invention, the system of the presentinvention allows the user to select a mode based on one or morebattery/power system characteristics. For example, in one suchembodiment, means (e.g., dial, menu based system on a visual display,buttons, etc.) are provided that allow the user to select the chargingcut-off voltage. Preferably the user is given four or more options suchas 3.8 volts, 3.9 volts, 4.0 volts, 4.1 volts and 4.15 volts.Alternately, the provided means allow the user to select the averagecharge, e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%.

In this alternate embodiment, means are preferably used to indicate tothe user both the advantages and the disadvantages for each selection.For example, a display monitor can graphically illustrate that as thecut-off voltage is increased, the user is gaining performance anddriving range while negatively impacting battery life. In one relativelysimple display, the user is shown a sliding scale (e.g., from minimumdriving range to maximum driving range) with an indicator on the scaleshowing the user's selection. In an example of a relatively complexdisplay, the system calculates the effects of the user's selection onpredicted battery life or on the vehicle's driving range.

In this alternate embodiment, preferably the power control subsystem 401sets additional system parameters based on the user's selection. Forexample, as the selected cut-off voltage is increased, the system canautomatically increase battery temperature as well as the cut-offvoltage, assuming that if the user selects a higher cut-off voltage,they are less interested in battery life and more interested inperformance. In at least one such embodiment, the power controlsubsystem uses a look-up table to determine appropriate batterytemperatures, charging characteristics, etc., all based on the user'sselection.

Mode Selection Means

The present invention can utilize any of a variety ofcharging/operational mode selection means. In a preferred embodiment, adisplay system is used, either alone with a touch-sensitive screen, ortogether with a plurality of switching means (e.g., toggle switches,push button switches, slide switches, etc.). For example, FIG. 5illustrates the display screen 500 of a touch-sensitive display system.Display screen 500 can be a stand-alone display screen or, as preferred,simply one display screen of a plurality of display screens comprising auser interface. Preferably this user interface allows the user toperform other functions associated with the operation of the vehicle,such as monitoring performance, monitoring battery life, monitoring thestate of charge of the battery, monitoring the remaining miles to driveon the current battery charge, adjusting system default settings, andother monitoring/operational functions. This same user interface,through additional screens, can also be used to provide the user withAC/heat controls, audio entertainment controls, cell phone controls,navigation system controls, and other convenience functions.

Display screen 500 includes a plurality of touch-sensitive buttons501-504 that correspond to the available charging/operational modes. Inone embodiment, touching one of the buttons 501-504 causes thecorresponding mode to be selected. Preferably the touched button ishighlighted to indicate the selection. In FIG. 5, button 502 is shown ashighlighted. In an alternate embodiment, a mode selection button must betouched followed by pushing (i.e., touching) a data entry button 505.Requiring the selection of two buttons, i.e., the mode button and theentry button, decreases the risk of an inadvertent mode change. In analternate embodiment that is intended to further reduce the risk ofinadvertent or unauthorized mode changes, after selecting a mode, orafter selecting a mode and touching the data entry button, a secondarymode selection screen is displayed that requests a user personalidentification number (PIN) or password.

Preferably the charging/operational mode selection means includes someindicator that helps the user to recognize the effects of their modeselection. In FIG. 5 indicator 507 graphically illustrates the effectsof the different modes on battery life. It will be appreciated thatthere are numerous ways in which such an indication can be made and thatare clearly envisioned by the inventors. For example, each button can becolor-coded. Alternately, a secondary display screen can be displayedwhen the user makes a selection, the secondary display screenhighlighting the effects of the selection. For example, when the userselects the Max Range Mode, the display screen may provide an indicationof the improved range (e.g., “range increased by 10%”) and the effectson battery life (e.g., “decreases long-term battery life”).

As previously noted, there are numerous other ways of configuring thecharging/operational mode selection means. For example, if anon-touch-sensitive display is used, preferably the screen isimmediately adjacent to a plurality of buttons, toggle switches, orother switching means that are used in conjunction with the display toprovide the selection means. FIG. 6 illustrates one such means. Asshown, screen 600 is configured so that the possible modes 601-604 aswell as other possible inputs 605-606 are immediately adjacent to hardbuttons, or other switching means, 607. It will be appreciated thatbuttons/switches 607 can similarly be used to provide other data inputsimply by re-configuring the display and associating the hard switches607 with other functions. As in the previous example, display screen 600includes an indicator 609 that shows the user the effects of theirselection.

In addition to a charging/operational mode selector that uses a displayscreen, e.g., displays 500 and 600, as previously noted a simplenon-display mode selector can also be used with the invention. Forexample, such a mode selector can be comprised solely of push buttons,toggle switches, slide switches, rotating switches, etc., which can belocated within the passenger compartment (e.g., on the dash, on theconsole, etc.) or elsewhere (e.g., near the plug-in receptacle on theoutside of the vehicle, preferably covered by a charging receptaclecover door). FIG. 7 illustrates one such charging/operational modeselector that does not require a display interface, rather it uses arotating switch 701. Indicators 703 surround switch 701, each of whichindicates a particular charging/operational mode. In the illustrationshown in FIG. 7, four charging/operational modes are shown with the MaxRange Mode selected. As in the prior embodiments, preferably anindicator is used, e.g., indicator 705, to insure that the userrecognizes the effects of their selection on a system parameter (e.g.,battery life).

In another embodiment, the charging/operational mode selection meansuses a voice recognition system such as those commonly used withon-board vehicle navigation systems. Preferably the voice recognitionsystem uses a display interface as well, thus simplifying system/userinteraction and providing the user with positive indicators when theirvoice inputs have been correctly accepted by the system.

Regardless of the selection means used, preferably the system includesone or more indicators that indicate the selected mode. Preferably theindicators are easily visible to insure that the user recognizes theselected mode. For example, four indicators can be located on thedashboard, easily visible to the driver, representing the fourcharging/operational modes illustrated in FIGS. 5-7. Preferably next toeach indicator is either a textual indicator of the mode, as shown inFIG. 8, or a symbolic indicator of the mode. In at least one embodiment,the indicators are also color coded, thus providing a secondaryindicator of selected mode. For example, in the indicators shown in FIG.8, indicator 801 is blue, indicator 803 is green, indicator 805 isyellow and indicator 807 is red. This is but one of numerous ways inwhich the selected mode can be highlighted to the driver of the vehicle.

In addition to, or instead of, an on-board charging/operational modeselection means, a remote selection means can be employed. The primaryadvantage of this type of mode selector is that it allows the user toremotely alter the charging/operational mode. For example, while on atrip the user may find that their trip has been extended and that theirvehicle will not be used for an extended period of time. Certain typesof remote mode selectors would allow the user to change the mode to theStorage Mode, thereby improving battery life.

FIG. 9 is a simplified illustration of a system for remotecharging/operational mode selection. As shown, the system includes aremote mode selector 901 and an on-board communication system 903 thatcommunicates with remote mode selector 901 via communication network905. On-board communication system 903 is coupled to on-board modeselection means 907, both of which are contained within vehicle 909. Inthe simplest form, remote mode selector 901 is an RF remote, thereforenot requiring a communication network. Due to the limited range of an RFremote, in a preferred embodiment remote 901 communicates via network905, network 905 being any of a variety of known network systems such ascellular, internet, satellite or other. For example, in one embodimentthe remote mode selector 901 is a computer or a web-browser on a cellphone and network 905 is an internet-based network system. Furtherdescriptions of suitable vehicle communication systems are given inco-pending U.S. patent application Ser. Nos. 11/818,838, filed Jun. 15,2007 and 11/779,678, filed Jul. 18, 2007, the disclosures of which areincorporated herein for any and all purposes.

In at least one embodiment of the invention, the system prompts the userto select a charging/operational mode. Preferably the user is promptedafter turning off the car, but prior to exiting the car, for examplewhen the user first turns the key (or other vehicle on/off controlswitch) from the operational/driving position to the standby/offposition. The user can be prompted by a tone or series of tones, by apre-recorded or synthesized voice, or by a display means (e.g., flashingindicator, flashing screen on the display interface, etc.), or acombination thereof.

Default System

In one preferred embodiment, the default mode for thecharging/operational mode selection system is the Standard Mode. In thisembodiment, the system resets to the default mode, i.e., Standard Mode,after each user selected charging/operational mode is complete. Thus,for example, if the user selects the Storage Mode, the system willremain in the Storage Mode as long as the vehicle remains in storage.Once the vehicle is taken out of storage, for example by operating thevehicle, the system automatically returns to the default mode.Similarly, if the user sets the system to the Performance Mode or theMax Range Mode, the vehicle stays in the selected mode during vehicleoperation, but returns to the default mode the first time the user turnsoff the car or the next time the vehicle is plugged into an externalpower source for charging.

In at least one embodiment of the invention, the user is able to selectthe default mode for the charging/operational mode selection system. Theuser is also able to select the temporary charging/operational modeusing the mode selection means as previously described. Preferably themode changes from the preferred mode to the default mode after a presetperiod of time, or after the occurrence of a particular event such asthe completion of the present driving cycle and the vehicle beingchanged from the operational mode to the charging mode, or after theoccurrence of a particular event such as the vehicle being changed fromthe charging mode to the operational mode.

In at least one embodiment of the invention, if the vehicle is notoperated for a preset period of time, the vehicle automatically switchesmode from the default mode (e.g., Standard Mode) to the Storage Mode.The vehicle preferably stays in the Storage Mode until the user eitheroperates the vehicle or actively selects a differentcharging/operational mode. Preferably in this embodiment the user isable to set the preset time period, for example by choosing from a listof time periods (e.g., 1 week, 2 weeks, 3 weeks, etc.). This optionallows the user to set-up the vehicle based on the user's particulardriving habits, thus insuring that the vehicle is not unintentionallyplaced in the Storage Mode.

In at least one embodiment of the invention, the user is able to switchmodes from the current mode to the Performance Mode while driving thevehicle. Preferably the switching means used to switch from the currentmode into the Performance Mode is different from, and in addition to,the normal user mode selection means. For example, in one embodiment ifthe user completely depresses the accelerator pad more than once withina preset time period, for example in a 3 second time period, than thecharging/operational mode switches to the Performance Mode. In analternate embodiment, if the user completely depresses the acceleratorpad more than twice within the preset time period than thecharging/operational mode switches to the Performance Mode. Preferablythe preset time period is preset by the vehicle's manufacturer.Alternately, the preset time period is preset, or configurable, by arepresentative of the manufacturer such as an authorized serviceprovider. Alternately, the preset time period is configurable by theuser. Preferably if an embodiment of the invention is used which allowsthe user to switch from the current mode into the Performance Mode whiledriving, the embodiment is also configured to automatically revert tothe Standard Mode, either after a predetermined time period (e.g., 24hours) or upon completion of the present driving period (i.e., whenpower is turned off and the vehicle enters the standby mode) or uponcompletion of the present driving cycle (i.e., when power is turned offand the vehicle is plugged in to recharge battery pack 403).

As will be understood by those familiar with the art, the presentinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. Accordingly, thedisclosures and descriptions herein are intended to be illustrative, butnot limiting, of the scope of the invention which is set forth in thefollowing claims.

1. An electric vehicle multi-mode battery charging and operating system,comprising: a battery charging system for charging a battery pack of anelectric vehicle, said battery charging system utilizing a cut-offvoltage selected from at least a first cut-off voltage, a second cut-offvoltage, and a third cut-off voltage; a battery cooling system forcooling said battery pack of said electric vehicle when said batterycharging system is coupled to a charging power source, said batterycooling system cooling said battery pack to a temperature within atemperature range selected from at least a first temperature range, asecond temperature range and a third temperature range; and means forselecting a preferred mode from a plurality of charging/operationalmodes, wherein said selecting means is accessible by a user of saidelectric vehicle, wherein a first mode of said plurality ofcharging/operational modes utilizes said first cut-off voltage and saidfirst temperature range, wherein a second mode of said plurality ofcharging/operational modes utilizes said second cut-off voltage and saidfirst temperature range, wherein a third mode of said plurality ofcharging/operational modes utilizes said third cut-off voltage and saidsecond temperature range, and wherein a fourth mode of said plurality ofcharging/operational modes utilizes said third cut-off voltage and saidthird temperature range.
 2. The electric vehicle multi-mode batterycharging and operating system of claim 1, wherein said charging powersource is an external power source.
 3. The electric vehicle multi-modebattery charging and operating system of claim 1, wherein said firstcut-off voltage is approximately 4.10 volts, said second cut-off voltageis approximately 3.80 volts, said third cut-off voltage is at least 4.15volts, said first temperature range is approximately 20° C. to 25° C.,said second temperature range is approximately 15° C. to 17° C., andsaid third temperature range is approximately 35° C. to 40° C.
 4. Theelectric vehicle multi-mode battery charging and operating system ofclaim 1, further comprising a battery heating system for preventing abattery pack temperature from falling below a preset temperaturethreshold when said battery charging system is coupled to said chargingpower source and when said fourth mode is selected by said selectingmeans.
 5. The electric vehicle multi-mode battery charging and operatingsystem of claim 4, wherein said preset temperature is approximately 33°C.
 6. The electric vehicle multi-mode battery charging and operatingsystem of claim 1, wherein said selecting means is comprised of atouch-sensitive screen.
 7. The electric vehicle multi-mode batterycharging and operating system of claim 6, wherein said touch-sensitivescreen is associated with a vehicle user interface system.
 8. Theelectric vehicle multi-mode battery charging and operating system ofclaim 1, wherein said selecting means is comprised of a display systemand a plurality of switching means.
 9. The electric vehicle multi-modebattery charging and operating system of claim 8, wherein said switchingmeans are selected from the group consisting of push-buttons, toggleswitches, rotating switches and slide switches.
 10. The electric vehiclemulti-mode battery charging and operating system of claim 1, whereinsaid selecting means is comprised of a plurality of switching means. 11.The electric vehicle multi-mode battery charging and operating system ofclaim 10, wherein said switching means are selected from the groupconsisting of push-buttons, toggle switches, rotating switches and slideswitches.
 12. The electric vehicle multi-mode battery charging andoperating system of claim 1, wherein said selecting means is a rotatingswitch.
 13. The electric vehicle multi-mode battery charging andoperating system of claim 1, wherein said selecting means is a voicerecognition system.
 14. The electric vehicle multi-mode battery chargingand operating system of claim 1, further comprising a communicationinterface in communication with a network, wherein said selecting meansis a remote mode selector in communication with said network, whereinsaid remote mode selector is separate from said electric vehicle. 15.The electric vehicle multi-mode battery charging and operating system ofclaim 1, further comprising an RF communication interface, wherein saidselecting means is an RF remote mode selector separate from saidelectric vehicle.
 16. The electric vehicle multi-mode battery chargingand operating system of claim 1, further comprising at least one modeindicator, wherein said at least one mode indicator indicates which modeof said plurality of charging/operational modes is selected by saidselecting means.
 17. The electric vehicle multi-mode battery chargingand operating system of claim 1, wherein said first mode of saidplurality of charging/operational modes is a default mode, said electricvehicle multi-mode battery charging and operating system furthercomprising means for switching from said preferred mode to said defaultmode upon the occurrence of a preset condition.
 18. The electric vehiclemulti-mode battery charging and operating system of claim 17, whereinsaid preset condition is changing from an operational vehicle mode to acharging mode.
 19. The electric vehicle multi-mode battery charging andoperating system of claim 17, wherein said preset condition is changingfrom a charging mode to an operational vehicle mode.
 20. The electricvehicle multi-mode battery charging and operating system of claim 17,wherein said preset condition is a preset period of time.
 21. Theelectric vehicle multi-mode battery charging and operating system ofclaim 1, further comprising means for selecting a default mode from saidplurality of charging/operational modes, wherein said default modeselecting means is accessible by a user of said electric vehicle, andwherein said electric vehicle multi-mode battery charging and operatingsystem further comprises means for switching from said preferred mode tosaid default mode upon the occurrence of a preset condition.
 22. Theelectric vehicle multi-mode battery charging and operating system ofclaim 1, further comprising means for prompting said user to select saidpreferred mode from said plurality of charging/operational modes usingsaid selecting means.
 23. A method of setting a charging/operationalmode of an electric vehicle, the method comprising the steps of:displaying a plurality of user accessible charging/operational modes;selecting a preferred mode from said plurality of user accessiblecharging/operational modes; displaying an indicator of said selectedpreferred mode; adjusting a charging cut-off voltage to a first cut-offvoltage in response to selecting a first mode as said preferred mode;cooling a battery pack of said electric vehicle to a battery packtemperature within a first range of temperatures in response toselecting said first mode as said preferred mode, wherein said step ofcooling said battery pack to said battery pack temperature within saidfirst range of temperatures is performed after said electric vehicle iscoupled to an external charging power source; adjusting said chargingcut-off voltage to a second cut-off voltage in response to selecting asecond mode as said preferred mode; cooling said battery pack of saidelectric vehicle to said battery pack temperature within said firstrange of temperatures in response to selecting said second mode as saidpreferred mode, wherein said step of cooling said battery pack to saidbattery pack temperature within said first range of temperatures isperformed after said electric vehicle is coupled to said externalcharging power source; adjusting said charging cut-off voltage to athird cut-off voltage in response to selecting a third mode as saidpreferred mode; cooling said battery pack of said electric vehicle tosaid battery pack temperature within a second range of temperatures inresponse to selecting said third mode as said preferred mode, whereinsaid step of cooling said battery pack to said battery pack temperaturewithin said second range of temperatures is performed after saidelectric vehicle is coupled to said external charging power source;adjusting said charging cut-off voltage to said third cut-off voltage inresponse to selecting a fourth mode as said preferred mode; and coolingsaid battery pack of said electric vehicle to said battery packtemperature within a third range of temperatures in response toselecting said fourth mode as said preferred mode, wherein said step ofcooling said battery pack to said battery pack temperature within saidthird range of temperatures is performed after said electric vehicle iscoupled to said external charging power source.
 24. The method of claim23, further comprising the step of reverting to a default mode from saidpreferred mode after a preset period of time, wherein said default modeis one of said plurality of user accessible charging/operational modes.25. The method of claim 23, further comprising the step of reverting toa default mode from said preferred mode after said electric vehiclecycles from an operational mode to a charging mode, wherein said defaultmode is one of said plurality of user accessible charging/operationalmodes.
 26. The method of claim 23, further comprising the step ofpreventing said battery pack temperature from falling below a presettemperature threshold when said battery charging system is coupled tosaid charging power source and when said fourth mode is selected as saidpreferred mode.
 27. The method of claim 23, further comprising the stepof heating said battery pack of said electric vehicle to said batterypack temperature above a preset temperature threshold when said batterycharging system is coupled to said charging power source and when saidfourth mode is selected as said preferred mode.
 28. An electric vehiclemulti-mode battery charging and operating system, comprising: a batterycharging system for charging a battery pack of an electric vehicle, saidbattery charging system utilizing a cut-off voltage selected from atleast a first cut-off voltage, a second cut-off voltage, and a thirdcut-off voltage, wherein said second cut-off voltage is higher than saidfirst cut-off voltage, and wherein said third cut-off voltage is higherthan said second cut-off voltage; a battery cooling system for coolingsaid battery pack of said electric vehicle when said battery chargingsystem is coupled to an external charging power source, said batterycooling system maintaining said battery pack within a temperature rangeselected from at least a first temperature range, a second temperaturerange and a third temperature range, wherein said second temperaturerange is colder than said first temperature range, and wherein saidthird temperature range is colder than said second temperature range; acharging/operational mode selector with at least four availablecharging/operational modes, wherein said charging/operational modeselector is accessible by a user of said electric vehicle, wherein afirst charging/operational mode defines a standard mode and utilizessaid second cut-off voltage and said second temperature range, wherein asecond charging/operational mode defines a storage mode and utilizessaid first cut-off voltage and said second temperature range, wherein athird charging/operational mode defines an extended driving range modeand utilizes said third cut-off voltage and said third temperaturerange, and wherein a fourth charging/operational mode defines anperformance mode and utilizes said third cut-off voltage and said firsttemperature range; and a mode display, wherein said mode displayindicates which charging/operational mode of said at least threeavailable charging/operational modes has been selected.